The Role of Confined Water in Ionic Liquid Electrolytes for Dye-Sensitized Solar Cells

Ionic liquids (ILs) provide an attractive medium for various chemical and redox reactions, where they are generally regarded as hydrophobic. However, Seddon et al. discovered that 4–10 wt % water absorbs into ILs that contain bulky anions, and Cammarata et al. found that the molecular state of water in ILs is dramatically different from that of bulk liquid water or that of water vapor. To determine the microstructure of water incorporated into ILs and the impact on properties, we carried out first-principles-based molecular dynamics simulations. We find water in three distinct phases depending on water content, and that the transport properties depend on the nature of the water phases. These results suggest that the optimal water content is ~10% mole fraction of water molecules (~1.1 wt %) for applications such as nonvolatile electrolytes for dye-sensitized solar cells (DSSCs). This suggests a strategy for improving the performance of IL DSSC by replacing water with additives that would play the same role as water (since too much water can deteriorate performance at the anode–dye interface)

Association between vitamin D level at birth and respiratory morbidities in very-low-birth-weight infants

Purpose This study aimed to evaluate vitamin D status at birth in very-low-birth-weight infants (VLBWIs: <1,500 g) and to determine the association between vitamin D level and respiratory morbidity. Methods A retrospective study was conducted at Soonchunhyang University Bucheon Hospital between November 2013 and November 2017. We collected blood samples and data on respiratory morbidity from 230 VLBWIs on the first day of life. Patients who were transferred to other hospitals (n=19), died before 36 weeks of gestational age (n=18), or whose blood samples were not collected immediately after birth (n=5) were excluded. Finally, 188 patients were enrolled. VLBWIs with different vitamin D levels were compared with respect to demographic features, maternal diseases, respiratory morbidities, and other neonatal diseases. Results The mean serum vitamin D level, as measured by 25-hydroxyvitamin D (25(OH)D), was 13.4± 9.3 ng/mL. The incidence of vitamin D deficiency (<20 ng/mL) was 79.8%, and 44.1% of preterm infants had severe vitamin D deficiency (<10 ng/mL). Logistic analysis shows that a low serum 25(OH)D level (<20 ng/mL) was a risk factor for respiratory distress syndrome (odds ratio [OR], 4.32; P=0.010) and bronchopulmonary dysplasia (OR, 4.11; P=0.035). Conclusion The results showed that 79.8% of preterm infants in this study had vitamin D deficiency at birth. Low vitamin D status was associated with respiratory morbidity, but the exact mechanism was unknown. Additional studies on the association between vitamin D level and neonatal morbidity are required

Causes and Treatment Outcomes of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in 82 Adult Patients

original article korean j intern med 2012;27:203-21

Endoscopic Submucosal Dissection Followed by Concurrent Chemoradiotherapy in Patients with Early Esophageal Cancer with a High Risk of Lymph Node Metastasis

Endoscopic submucosal dissection is recommended as an alternative therapy for early esophageal cancer. However, achieving curative resection in this procedure remains controversial since precise prediction of lymph node metastasis can be difficult. Here, we present the preliminary results of endoscopic submucosal dissection followed by concurrent chemoradiotherapy for early esophageal cancer with a high risk of lymph node metastasis. From May 2006 to January 2014, six patients underwent concurrent chemoradiotherapy after endoscopic submucosal dissection with a median follow-up period of 63 months. No complications were encountered during concurrent chemoradiotherapy. Although local recurrence did not occur in all patients, two patients were diagnosed with metachronous cancer. Overall, the survival rate was 100%. Thus, endoscopic submucosal dissection followed by concurrent chemoradiotherapy may be a feasible treatment for early esophageal cancer in patients with a high risk of lymph node metastasis. Future prospective large-scale studies are warranted to confirm our results

A Review of Suicide Risk Assessment Tools and Their Measured Psychometric Properties in Korea

While there has been a slew of review studies on suicide measurement tools until now, there were not any reviews focusing on suicide assessment tools available in Korea. This review aimed to examine the psychometric properties of tools developed in Korea or the translated versions from the original tools in their foreign language and to identify potential improvements and supplements for these tools. A literature search was done using the Korean academic information search service, Research Information Service System, to identify the suicide measures to be included in this review. Abstracts were screened to identify which measures were used to assess suicide-related factors. Based on the established inclusion and exclusion criteria, 18 tools remained and we assessed their psychometric properties. The current review indicated several major findings. First, many of the tools did not report predictive validity and even those with predictive validity were based on past suicide attempts. Second, some of the tools overlooked the interactive component for the cause of suicide. In addition, information to supplement the self-reported and clinician-administered reports by collecting reports from the subjects' families and acquaintances is needed. It is also important to develop a screening tool that examines other aspects of an individual's personal life, including unemployment, bereavement, divorce, and childhood trauma. Moreover, tools that have been studied in more diverse groups of the population are needed to increase external validity. Finally, the linguistic translation of the tools into Korean needs to consider other cultural, social, and psychological factors of the sample of interest

Impact of frailty on early rhythm control outcomes in older adults with atrial fibrillation: A nationwide cohort study

PurposeRhythm-control therapy administered early following the initial diagnosis of atrial fibrillation (AF) has superior cardiovascular outcomes compared to rate-control therapy. Frailty is a key factor in identifying older patients’ potential for improvement after rhythm-control therapy. This study evaluated whether frailty affects the outcome of early rhythm-control therapy in older patients with AF.MethodsFrom the Korean National Health Insurance Service database (2005–2015), we collected 20,611 populations aged ≥65 years undergoing rhythm- or rate-control therapy initiated within 1 year of AF diagnosis. Participants were emulated by the EAST-AFNET4 trial, and stratified into non-frail, moderately frail, and highly frail groups based on the hospital frailty risk score (HFRS). A composite outcome of cardiovascular-related mortality, myocardial infarction, hospitalization for heart failure, and ischemic stroke was compared between rhythm- and rate-control.ResultsEarly rhythm-control strategy showed a 14% lower risk of the primary composite outcome in the non-frail group [weighted incidence 7.3 vs. 8.6 per 100 person-years; hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.79–0.93, p &lt; 0.001] than rate-control strategy. A consistent trend toward a lower risk of early rhythm-control was observed in the moderately frail (HR 0.91, 95% CI 0.81–1.02, p = 0.09) and highly frail (HR 0.93, 95% CI 0.75–1.17, p = 0.55) groups.ConclusionAlthough the degree attenuated with increasing frailty, the superiority of cardiovascular outcomes of early rhythm-control in AF treatment was maintained without increased risk for safety outcomes. An individualized approach is required on the benefits of early rhythm-control therapy in older patients with AF, regardless of their frailty status

Phonon-suppressing intermolecular adhesives : catechol-based broadband organic THz generators

Solid-state molecular phonons play a crucial role in the performance of diverse photonic and optoelectronic devices. In this work, new organic terahertz (THz) generators based on a catechol group that acts as a phonon suppressing intermolecular adhesive are developed. The catechol group is widely used in mussel-inspired mechanical adhesive chemistry. Newly designed organic electro-optic crystals consist of catechol-based nonlinear optical 4-(3,4-dihydroxystyryl)-1-methylpyridinium (DHP) cations and 4-(trifluoromethyl)benzenesulfonate anions (TFS), which both have multiple interionic interaction capability. Interestingly, compared to benchmark organic crystals for THz generators, DHP-TFS crystals concomitantly achieve top level values of the lowest void volume and the highest crystal density, resulting in an exceptionally small amplitude of solid-state molecular phonons. Simultaneously achieving small molecular phonon amplitude, large optical nonlinearity and good phase matching at infrared optical pump wavelengths, DHP-TFS crystals are capable of generating broadband THz waves of up to 16 THz with high optical-to-THz conversion efficiency; one order of magnitude higher than commercial inorganic THz generators